The present invention relates generally to the field of electrical computers and digital processing systems, and more particularly to virtual memory addressing.
Virtual storage (sometimes also called virtual memory) can be allocated or deallocated. A frame backs a range of virtual storage. When a system releases virtual storage, a frame is either released or retained. If a frame is released, a system makes the frame available to back any virtual storage. Alternatively, a frame is retained to back virtual storage (sometimes also called mapping) and sensitive information from the frame is erased. A frame retained to back virtual storage is sometimes also called a freemained frame. A freemained frame is retained for an eventuality that a virtual storage range is reused. Freemained frames are retained to improve system performance. Historically, efforts have been made to minimize adverse system impacts. To do so, count thresholds are set for the number of freemained frames that are retained. Freemained frames are sometimes also described as page frames backing deallocated virtual storage.